NMR-Based Metabolomic Comparison of Brassica oleracea (Var. italica): Organic and Conventional Farming

Abstract

Brassicaceae family provides several crops which are worldwide known for their interesting phytochemical profiles, especially in terms of content of glucosinolates. These secondary metabolites show several beneficial effects toward consumers’ health, and several studies have been conducted to identify cultivation factors affecting their content in crops. One of the agronomic practices which is attracting growing interest is the organic one, which consists in avoiding the use of mineral fertilizers as well as pesticides. The aim of this study is to define the metabolic profile of Brassica oleracea (var. italica) and to compare the samples grown using organic and conventional fertilization methods. The hydroalcoholic and organic extracts of the samples have been analyzed by NMR spectroscopy. Forty-seven metabolites belonging to the categories of organic acids, amino acids, carbohydrates, fatty acids, sterols, and other molecules have been identified. Thirty-seven metabolites have been quantified. Univariate and multivariate PCA analyses allowed to observe that the organic practice influenced the nitrogen transport, the carbohydrate metabolism, the glucosinolate content and the phenylpropanoid pathway in B. oleracea (var. italica).

Byproducts of Globe Artichoke and Cauliflower Production as a New Source of Bioactive Compounds in the Green Economy Perspective: An NMR Study

“…All identified amino acids ( Table 1 ) were already noticed in the literature [ 39 ], except one. Here, the presence of S -methyl-L-cysteine-sulfoxide (methiin) in the NMR spectra of aqueous extracts of cauliflower is reported for the first time.…”

“…Both aqueous and organic fractions of all three types of tissues were examined by NMR. The assignment of NMR spectra ( Figure 3 ) was based on 1 H and 13 C NMR metabolite profiling of the eatable part (floret) reported in the literature [ 39 ] and the same set of 2D NMR experiments used for globe artichoke extracts ( Figures S15–S23 in the Supplementary Materials ).…”

“…NMR spectroscopy [ 28 ] has been successively applied for the comprehensive metabolite composition analysis of different plant tissues [ 29 ] including leaves [ 30 ], shoots [ 31 ], flowers [ 32 ], roots [ 33 ], tubers [ 34 ], and fruits [ 35 ]. Moreover, NMR spectroscopy has been already applied for the investigation of metabolite profiles of eatable parts of globe artichoke (entire heads or heads divided in external bracts and heart tissues) [ 36 , 37 , 38 ] and cauliflower [ 39 ], whereas a comprehensive NMR-based metabolite profiling of non-eatable parts of globe artichoke and cauliflower is still absent. The present study aimed to fill this gap by extending NMR characterization to byproducts, including also the identification of apolar metabolite profiles disregarded in the previous NMR studies.…”

Seasonal Variation of Glucosinolate Hydrolysis Products in Commercial White and Red Cabbages (Brassica oleracea var. capitata)

“…In the present study, I3M levels of organic white and red cabbages from ORG 1 were often higher, compared to the cabbages from the conventional food retailers CON 1 and CON 2 ( Figure 1 C). Likewise, using NMR spectroscopy, Lucarini et al (2020) recently also found nearly 3 times as much I3M in organic broccoli compared to conventionally grown ones [ 33 ]. In that study, the main difference in both farming practices was the fertilization practice, as no pesticides were used.…”

“…In that study, the main difference in both farming practices was the fertilization practice, as no pesticides were used. While the same amount of nitrogen was supplied to the soil, for conventional broccoli with 0.2 t/ha urea and 15 t/ha bovine manure were applied, while organic grown broccoli was fertilized with 28 t/ha [ 33 ]. Nevertheless, increased I3M biosynthesis could be also explained due to the absence of chemical pesticides in organic cultivation practices, resulting in the stimulation of indole GLS biosynthesis upon herbivory damage via the methyl jasmonate signalling pathway [ 34 ].…”